Critical values lists have been used for many years to decide when to notify physicians and other caregivers of potentially life-threatening situations; however, these lists have not been studied widely.
To investigate critical values lists in institutions participating in the College of American Pathologists Q-Probes program and to provide suggestions for improvement.
A total of 623 institutions voluntarily participating in the Q-Probes program.
A multipart study in which participants responded to information from preprinted lists, collected information about current practices, completed a questionnaire, monitored critical values calls, reviewed patients' medical records, and surveyed nursing supervisors and physicians about critical values.
Defining critical values systems, including lists, personnel, costs, processes, usefulness, and related medical outcomes.
Critical values lists were determined for routine chemistry and hematology analytes and were found to vary widely among participants. In contrast, more than 95% of participants reported positive blood cultures, cerebrospinal fluid cultures, and toxic therapeutic drug levels as critical values. Based on more than 13 000 critical values, participants' data showed that most critical values reports (92.8%) were made by the person who performed the test, and that 65% of reports for inpatients were received by nurses. For outpatients, physicians' office staff received the largest percentage (40%) of reports. The majority of participants (71.4%) had no policy on how repeat critical calls should be handled. On average, completion of notification required about 6 minutes for inpatients and 14 minutes for outpatients. Slightly greater than 5% of critical value telephone calls were abandoned, with the largest percentage abandoned for outpatients. More than 45% of critical values were unexpected, and 65% resulted in a change in therapy. Although only 20.8% of 2301 nursing supervisors thought critical values lists were helpful, 94.9% of 514 physicians found critical values lists valuable.
Critical values systems were medically important, highly variable, but also costly practices for participants. We propose a number of recommendations for improvement, including that the critical values list should be approved by the medical staff, each laboratory should develop a written policy for handling initial and repeat critical values reports, a foolproof policy should be established to report results from calls abandoned, and efforts at automating the process should become widespread.